Treggings aren't entirely new: They were first introduced in Balmain's fall 2009 collection, according to Fashion 101. But now that treggings are available at H&M, they're sure to become a major trend.

H&M's new slim-fit treggings are described as "superstretch twill with concealed elastication at waist. Slim legs with center seams."

So in other words, they're basically a nicer form of "jeggings" — which, of course, is a fusion of jeans and leggings — that you can wear if jeans aren't acceptable at your workplace.